Protecting fabric against rot



. cuticle of the Patented Nov. 20, i923,

westeeerie BERNARD WOLCOTT, OF BUFFALO, NEW YORK, AND CLAY LQJENNISON, OE WASHING- TON, DISTRICT OF COLUMBIA."

PROTEQTITNG FABRIC AGAINST BOT.

No Drawing.

To all whom it may concern:

Be it known that we, (1) BERNARoWoL- com and (2) CLAY L. JENNISON, citizens of the United States, residing at (1 Bufialo and (2) Washington, in the D'1Stl l0t of Tolumbia, in the county of 1) Er e and State of (1) New York, have Invented certain new an useful Improvements n Protecting Fabrics Against Rot, of which the following is a specification.

As is well known, moulds and bacteria (the number of species responsible for the deterioration is large, but chief among them are species of alternaria, of cladospomum, and some mucors) attack all cellulosic mate rial under conditions which usually prevail in industrial use. The simultaneous pccurence of different kinds of moulds seem to play an important part, and the production of pink and yellow discolorations is probably due, to the growth of a mucor and a mould producing a substance having a pink or yellow appearance.

The fabric used for boat sails, awnings,

' wearing apparel in hot climates, shoe-linings,

agricultural purposes and cotton or other cellulosic materials exposed to weather, are subject to this attack, as these conditions are favorable to bacterial and mould growth, thereby causing a disintegration, rotting or mildewing of the material.

Heretofore, processes have so treating the cellulosic material as to make them impervious to rot. These processes have innumerable disadvantages. They do not render the cloth permanently immune to attack, and frequently weaken the tensile strength and alter other physical characteristics of it (appearance, pliability, inflammability, etc.,) and the rot-proofing ingredi nts used are usually either a surface coating or cellulosic solvent which considerably we'tkens the fabric by attacking the fibre. Very often the ingredients can be washed or rubbed OE, and generally speaking are not'entirely satisfactory. These processes also have a detrimental effect not only on the machinery used in the finishing of the material into merchandisable objects but also upon the workmen so employed. The cost of the processes now in use is usually quite high.

\Ve have discovered that a new rot and bacteria proof material may be produced in which the tensile strength has not been de- Application filed. December 10,

been used for color,

1921. Serial No. 521,470.

creased, the cut'icledestroyed or the structure of the individual fibresfwhich make up the fabric, altered as to appearance, structure or pliability, so that the new fabric can be used' in exactly the same manner as the original cloth.

This product we obtain by subjecting. the fabric or yarn to an esterifying process of which the following is an example.

We are aware that methods of formylating and acetylating cellulose are not entirely new but the low formyl, acetyl, propyl and butyl esters of cellulose produced by us for this particular purpose are new industrial compounds and we claim priority in their production as such as in their use as rot and mildew proofing materials.

The following is an example of the manner in which the process of making rot and mildew proof material of cellulosic composition ma be carried out but the invention is not limited to this particular example.

The cellulosic material, either in the form of yarn or fabric,

should first be mercerized aflinity for substantive dyestuffs; for example, cotton duck is immersed in caustic soda solution of 60 Twaddell for ten to fifteen minutes at 20 (3., washed, acidified and dried. The material is then treated in either an acetylating, butylating, formylating or propylating bath, or mixture of these baths.

i As a specific example, 100 parts of cellulose in the form of yarn, canvas, duck,for fabric which may have been previously mercerized are placed in a butylating bath consisting of 400 parts by weight of normal butyric acid and 300-400 parts by weight of but ric anhydride and 20-40 parts by weig t of a condensing agent. Such condensing agents may be sulphuric acid or its modifications; organic sulphates. or metallic chlorides. The butyric acid may be replaced by acetic or other organic acidsor by inert materials suchas benzol, carbon tetrachloride, etc., as their function in the bath is simply as a diluent and medium for more efficient penetration of the cellulose by the anhydride.

The treatment, as "before explained, is carried out either under atmospheric or increased pressure, if found necessary, and the temperature is gradually increased to the point necessary for the desired esterificavacteristics of the original Heretofore, low acetylated esters of cellution with the particular condensing agent used as well as, the kind of cellulose employed. In the case of sulphuric acid the temperature should not be allowed to exceed 3040 C. for complete low-esterification whereas with organic sulphates and metallic chlorides the temperature may be allowed to reach 80 (l, for similar results. The time of treatment is short, not more than one hour is sufficient to produce the desired esterification (mono or (ii). The material is then removed from the bath and washed entirely free of butyric acid. The acid free material can then be stabilized by boiling in water. The material when dried is absolutely impervious to rot, mildew and bacterial attacks, and retains its tensile strength-and the otheii plliysical charc ot lose have been produced which resist direct cotton dyestuffs. Our product differs from other low acetylated esters of cellulose in that a cellulose is produced which has a strong affinity for direct cotton dyestufis, and may or may not, as the occasion demands, retain the lustre and other advantages for which cellulosic materials are mercerized.

The treatment as above described produces some increase in weight, but, to obtain the best results, this increase should not be more than 13 per cent, and is preferably less. It has been found that the preliminary treatment with caustic alkali (mercerization) eflectuallyprevents the formation of the higher '(above dior mono) esters. As above indicated, the time of treatment is short, not more than one hour, and a shorter time is usually sufficient.

By low cellulosic esters are meant those esters not soluble in the common organic solvents in which are soluble the higher ra'raere esters, such as 'tri-acetate and tri-hydroacetate. 1

We claim:

1. A cellulosic material consisting of yarn or fabric, resistant to rot and bacteria, and having the characteristics of the product such as is produced by first niercerizing the yarn or fabric and then subjecting the fabric or yarn to an esterifying treatment sufficient to produce only low cellulosic esters.

2. The process of making cellulosic materials, in the form of yarn or fabric, rot and bacteria proof which consists in mercerizing the yarn or fabric and then treating the yarn or fabric with a fatty acid anhydride in presence of a condensing a nt and a diluent, the time of treatment ing so short that only low cellulosic esters are produced.

3. The process of making cellulosic ma terials, in the form of yarn or fabric, rot and bacteria proof which consists in mercerizing the yarn or fabric and then treating the yarn or fabric with a fatty acid anhydride in presence of a condensing agent and a diluent, without increasing the weight more than 13%.

4. The process of making cellulosic ma terials, in the form of yarn or fabric, rot and bacteria proof which consists in mercerizing the yarn or fabric and then treating the yarn or fabric with a fatty acid anhydride in presence of a condensing agent and a diluent, without increasing the weight more than 13%, the time of treatment being so short that only low cellulosic esters are produced.

lln testimony whereof, we ailix our signatures.

WOLCUTT. JENNlSfDN. 

